This invention relates generally to the field of jet drop recording, and more particularly to a stimulating plate for use in jet drop recorders such as shown in U.S. Pat. No. 3,882,508 and U.S. application Ser. No. 828,274, filed Aug. 29, 1977, both assigned to the assignee of the present invention.
As discussed in the aove '508 patent, the ink jets may be stimulated for controlled break-up into discrete droplets by applying suitable acoustical energy to the orifice plate itself. The orifice plate is bound to a plate holder which has an elongated opening which decreases in width with distance from the point where the orifice plate is stimulated. When the orifice plate is properly bonded to the orifice plate holder, the acoustical energy tends to be confined within the opening, due to the effective greater mass of the orifice plate holder along the edges of the opening. The narrowing of the opening is calculated to offset the attenuation of the acoustical energy so that the amplitude remains constant for uniform stimulation of the ink jets.
Alternatively, the body of ink within the recording head may be stimulated. This may be done, for example, by direct fluid coupling from a pressure plate opposite the orifice plate, as disclosed in the above '274 application. Again, the acoustical energy is most effectively utilized when it is confined to the region of the stimulating plate which is in contact with the body of ink.
As will be appreciated, the above configurations are sensitive to the nature and quality of the bond between the stimulating plate and the balance of the ink jet recording head. If the bond is irregular or weak, acoustical energy will be lost through the interface. This can also generate undesired reflections and otherwise interfere with the proper stimulation of the ink jets. Further, direct stimulation of the bond can fatigue and weaken it.
A need thus remains for a structure which separates the acoustical energy from the bond, and which contains the acoustic energy within the stimulating plate independently of, and substantially unaffected by, the bond between the stimulating plate and the balance of the ink drop recording head.